1. Field of Invention
The present invention relates to a construction block for use in masonry walls and, more particularly, to an insulated concrete construction block provided with improved insulating features which minimize thermal conduction through the block itself and through mortar joints between adjacent blocks in a masonry wall.
2. Description of the Prior Art
Conventional masonry construction of buildings employs pre-cast concrete blocks arranged end to end in rows and secured together by vertical mortar joints between adjacent blocks. Successive rows of blocks are secured to those below by horizontal mortar joints. Generally, the concrete blocks have a hollow interior to reduce the weight and facilitate handling of the blocks by workmen. One widely used construction block includes a central web extending transversely across the hollow interior of the block to connect the side walls of the block and preserve its strength.
Generally, such conventional construction blocks have relatively poor insulative value. The concrete material of the block allows appreciable thermal conduction, particularly at the end walls and central web where straight conductive paths are provided which allow direct heat conduction between the inner and outer side walls of the block. In addition, when such conventional blocks are assembled in a masonry wall, the vertical mortar joints between adjacent blocks and the horizontal mortar joints between successive rows of blocks are poorly insulated. Typically, air spaces in the mortar joints between the blocks allow sufficient air circulation to result in loss of heat by convection. Similarly, air is able to circulate through the hollow interior of the blocks resulting in additional loss of heat. Thus, such a masonry wall has usually been insulated by installation of a separate insulative barrier, e.g., conventional studs or furring strips with fiberglass or other insulation, on the inner face of the wall.
Although it has been proposed to utilize insulation inserts in the hollow interior spaces of conventional masonry blocks, such arrangements have not provided satisfactory insulative characteristics because of the loss of heat by conduction through the central web and end walls of the block. Further, no provision has been made to prevent loss of heat through the mortar joints between adjacent blocks.
In addition, various proposals have been made in the prior art to provide alternate forms of insulated masonry blocks by eliminating the centrally located transverse web of the conventional block and providing other interior configurations to achieve one or more hollow insulating spaces for receiving insulating material within the block. However, such proposals have generally sacrificed the overall strength of the conventional block without appreciably improving its insulative characteristics. Moreover, the complex internal configuration of such insulated blocks has made the blocks difficult and expensive to manufacture and install. Consequently, such insulated masonry blocks have not received widespread acceptance in the construction industry.
Nevertheless, because of the presently increasing concern about dwindling sources of conventional fossil fuels and the need to adequately insulate building walls, there is definitely a need for an insulated construction block which is simple and effective in design and capable of manufacture and installation at reasonable cost. A primary consideration in the design of a satisfactory insulated construction block is to maximize the insulative properties without sacrificing the strength of the block. To limit heat loss through the concrete material of the block itself, it is necessary to achieve a concrete block structure which eliminates direct paths for thermal conduction through the block. Furthermore, it is important that the construction block achieve adequate insulation in the mortar joints between adjacent blocks in the same row and between successive rows of blocks.